Natural Gas- its Characteristics and Safety Requirements...

Natural Gas- its Characteristics and Safety Requirements Natural gas (NG)  is a fuel gas which is used in steel plants as an auxiliary fuel for injection in blast furnace, for the production of gas based direct reduced iron, and for heating in various furnaces subject to local availability and the cost. NG is an environmentally friendly non renewable fossil fuel which is found in underground deposits in its gas phase. It exists as a gas under atmospheric conditions. It is basically a hydrocarbon gas mixture consisting primarily of methane. It is a clean fuel with a high efficiency. NG is normally supplied as (i) piped natural gas (PNG),  (ii) compressed natural gas (CNG), and (iii) liquefied natural gas (LNG). Modes of handling natural gas is given in Fig 1. Fig 1 Modes of handling natural gas NG is transported normally to long distances (up to 5000 kms) through a pipeline net work. The pressure of NG in the pipeline depends on several factors which include (i) quantity of gas to be transported, (ii) diameter of the pipeline,  (iii) the distances involved, and (iv) the safety of the gas pipeline and environment. However at the consumer end the pipeline pressure is generally less than 16 atmosphere. CNG is a form of natural gas which undergoes compression (200 to 250 kg/sq cm) into containers wherefrom it is relayed to consumers who, due to geographic and other reasons are incapable of connecting into the NG pipeline. CNG is storable. Unlike NG conveyed via pipelines and immediately consumed (similarly to electricity), CNG can be used for storage and for discontinuous utilization. NG compression into containers raises risk levels. LNG is made by cooling natural gas to a temperature of minus 162 deg C. At this temperature, natural gas becomes...